Infant Head Lag

Excerpt

Infants generally have a large head compared to the rest of their habitus, and the cervical group of paraspinal muscles is relatively weak at birth. Hence the reason for the notable head lag, especially during the first few weeks of life. During this stage, caregivers routinely support the infant's head until neck control is achieved. The gross motor skill development in infants typically follows a cephalocaudal sequence, and the gain of postural control heralds it. Postural control is an infant's ability to stabilize the center of their body mass/trunk with a dynamic or static base. This innate maturational process of the neck and trunk muscles is expected to evolve rapidly during the infancy stage. When an infant is pulled by the hand from a lying to sitting position, the expected response is to activate the head righting reflex and maintain the head position in line with his/her shoulders. Conversely, infant head lag is observed when the head seems to flop around or lags posteriorly behind the trunk during the pull-to-sit maneuver.

Several articles have maintained that head lag should be absent by age 3 to 4 months when infants typically experience an increased ability to control their neck muscles. Once neck control is attained, infants participate actively in a normal pick-up routine by stiffening their neck muscles while tensing up their trunk to decrease the lag between the chin and chest. Persistent head lag beyond age 4 months has been associated with poor neurodevelopmental outcomes.

There is a higher incidence of head lag amongst preterm neonates and infants with cerebral palsy, and it is a likely predictor of developmental outcome. It may, however, not be accurate in predicting neurobehavioral effects when used as an isolated metric. A possible explanation could be that assessing one isolated response is not enough to predict neurodevelopmental outcomes accurately. Many studies have suggested that a combination of neonatal responses, like reflex responses, postural reactions, and tone, may hold the potential to predict alteration in brain development correctly.

Studies have also shown that head lag combined with other early childhood developmental alterations may be intricately linked with a higher risk of autism in specific populations. Head lag was more commonly observed in siblings of children with autism spectrum disorder (ASD) than low-risk infants. Similarly, developmental problems relating to postural instability and axial hypotonicity have been described in infants with ASD.